1. Field of the Invention
The present invention relates to connectors for joining the ends of successive lengths of pipe or conduit and/or connecting a pipe or conduit to a housing or other mounting surface wherein the connection will be exposed to axial, transverse and bending vibrations. In particular, the present invention relates two connectors for joining pipes to one another or to other structures such as exhaust manifolds in exhaust systems for vehicles.
2. The Prior Art
It is well known that, in vehicle exhaust systems, the internal combustion (i.c.) engines produce significant amounts of vibration in the exhaust system. Operation of the motor at continuous speeds for prolonged periods of time can, especially, produce what are known as harmonic vibrations which can cause significant deflection in extended lengths of exhaust pipe and at locations where such pipes are mounted to structures such as brackets, engine manifolds and the like. Repeated deflections and vibrations along the exhaust pipe system can, in turn, cause the structures to weaken with time and ultimately fail. Further, such harmonic vibrations can also be transmitted through the exhaust pipes to the mountings of the pipes, promoting the loosening of the mountings, which can result in the sudden displacement of one or more components of the exhaust system, with the potential for both personal injury and equipment damage.
In addition to the vibrations caused by the operation of the engine of the vehicle, an exhaust system is also subjected to various tension, compression and bending forces which also arise during the operation of the vehicle. While individual exhaust system components could be made stronger and more massive to resist failure by fatigue, such constructions would be undesirable due to weight considerations. Further, by making individual elements stiffer, the vibrations are merely transmitted throughout the exhaust system to the mounting or other components and are not reduced or eliminated. Accordingly, it is desirable to isolate the exhaust system, or at least components of the system, from such vibrations and forces.
It is known that if the pipes of an exhaust system are divided and separated by non-rigid connections, rather than being constructed as continuous extended lengths, the development of harmonic vibrations from the motor is precluded or reduced. Such non-rigid connections can be advantageously employed to absorb other tension, compression and bending forces, apart from and in addition to the motor vibration.
It is therefore desirable to provide a connector for joining a length of exhaust pipe, to another pipe or to a mounting, such as an engine manifold which connector joins the components in a non-rigid fashion and is capable of decoupling the consecutive pipes or other components to absorb tension, compression and bending forces, as well as vibrational forces, without transmitting them from one exhaust system component to the next.
Typical prior art flexible connectors often require welds at both ends in order to achieve a strong, substantially fluid-type connection between the connector and the other exhaust system components to which they are attached. It would be desirable to avoid the use of welds whenever possible, as such welds take time to perform, adding to the installation time of the connector and increasing the overall assembly time of the vehicle or apparatus to which they are being attached.
In addition, such welds are often difficult to place properly, often requiring additional complexity in the construction of the flexible connector in order to provide working space for accomplishment of the weld. Still further, there is always a possibility of a small flaw in the weld, leading to possible leakage of harmful exhaust gases, and/or the introduction of a physical weakness in the structure of the flexible connector attachment, leading to the expenditure of additional time for double checking the quality of each weld being performed.
Also, welds are skill and labor intensive and add significant costs to such flexible connectors often amounting to a substantial percentage of the overall costs of the component.
Flexible exhaust system connectors, especially those which are used in connecting the exhaust manifold of an engine to the "down pipe" leading to the catalytic converter, are additionally under the constraint of having to accommodate the vibration of the engine while at the same time having to be physically small in order to fit into the cramped space of the engine compartment. In the prior art, it has been known for the connectors used in joining exhaust manifolds to the pipes leading to the catalytic converter to take the form of ball joint type connectors, inasmuch as such ball joint type connectors typically have a relatively small envelope and can fit into tight spaces. However, ball joint connectors are typically not completely sealed and can be prone to a certain amount of leakage when they are overly extended or compressed. In view of ever increasing constraints of the pollution levels which internal combustion engines are permitted to produce, as well as safety concerns regarding the leakage of exhaust gases in engine compartments, the use of such ball joint type connectors is becoming undesirable and may become prescribed by law.
Accordingly, it is desirable to provide an alternative vibration decoupling exhaust system connector which has the functional advantages of a ball joint type connector in that it can absorb or accommodate vibratory forces and can fit into a small envelope but is capable of providing more complete sealing and resistance to leakage of exhaust gases.
These and other objects of the invention will become apparent in view of the present specification including claims, and drawings.